| [GMCnet] alternator wiring [message #331654] |
Wed, 02 May 2018 13:51  |
Ek_Lektro
Messages: 167
Registered: March 2011
Karma: 2
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Greetings GMC friends;
a couple years ago I was having problems with an alternator putting out 16.5 volts and blowing headlights (a problem that seemed to start when i had an anonymous mechanic do an alternator swap for me). Back then, somebody on this list gave me a step-by-step process to check and make sure that the 2 wires on the left side were not reversed. I can’t seem to find this email, so if anybody here could remind me of the process, i’d greatly appreciate it! (Also,. i recall reading here somewhere that having a loose wiring connection with an APC circuit inline could also cause high voltage output from the alternator?) Just trying to get to the bottom of this… once and for all! Thanks much,
Greg
’78 Eleganza II
and ’76 Birchaven cut-down 21 footer
(might consider selling! can’t keep up with 2 coaches...)
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| Re: [GMCnet] alternator wiring [message #331658 is a reply to message #331654] |
Wed, 02 May 2018 14:43  |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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Senior Member |
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I am just trying to see how they could possibly be reversed. The wires are in a connector that is keyed so that it can only go into the alternator one way.
Here are your step by step instructions:
1 grasp connector
2 try to slide the connector into the alternator.
3 if it doesn’t fit go to step 4
4 turn the connector 180 degrees and plug it in!
Unless he pulled the wires from the connector — but what kind of mechanic would do that?
If your voltage sense wire has a loose connection
It could be read as low voltage and cause the voltage regulator to step up the charge voltage. This could happen whether you have an APC or not.
Emery Stora
77 Kingsley
Frederick, CO
> On May 2, 2018, at 12:51 PM, Ek_Lektro wrote:
>
> Greetings GMC friends;
> a couple years ago I was having problems with an alternator putting out 16.5 volts and blowing headlights (a problem that seemed to start when i had an anonymous mechanic do an alternator swap for me). Back then, somebody on this list gave me a step-by-step process to check and make sure that the 2 wires on the left side were not reversed. I can’t seem to find this email, so if anybody here could remind me of the process, i’d greatly appreciate it! (Also,. i recall reading here somewhere that having a loose wiring connection with an APC circuit inline could also cause high voltage output from the alternator?) Just trying to get to the bottom of this… once and for all! Thanks much,
> Greg
> ’78 Eleganza II
> and ’76 Birchaven cut-down 21 footer
> (might consider selling! can’t keep up with 2 coaches...)
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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| Re: [GMCnet] alternator wiring [message #331663 is a reply to message #331654] |
Wed, 02 May 2018 17:14 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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Let me re emphasize what Emery said. The APC is NOT a source of the potential problem. It is the connection to the alternator which is a female spade connector spade that could be on the APC or on the cable if no APC is installed.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] alternator wiring [message #331680 is a reply to message #331663] |
Thu, 03 May 2018 08:41 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
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Senior Member |
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If someone has replaced the connector at the end of the alt wire it is
quite possible the wire spades got switched when inserted into the new
connector body. Seen that.
Sully
77 eleganza 2
Bellevue
On Wed, May 2, 2018 at 3:22 PM Ken Burton wrote:
> Let me re emphasize what Emery said. The APC is NOT a source of the
> potential problem. It is the connection to the alternator which is a female
> spade connector spade that could be on the APC or on the cable if no APC
> is installed.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
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Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: [GMCnet] alternator wiring [message #331681 is a reply to message #331654] |
Thu, 03 May 2018 09:13 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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Those connections are not weather tight and subject to oxidation especially on vehicles that sit long periods. I have recommended Caig Deoxit D5 spray in the past for such uses. Also do not rule out a bad connection at the isolator or bad isolator, but check what others have said first.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] alternator wiring [message #331789 is a reply to message #331654] |
Mon, 07 May 2018 11:30 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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If the sense wire opens, the output voltage will climb to the internal limit value - 18 Volts or so. This will Break Things. If the 12V 'on' wire opens, the alternator will produce no output. The most common point of failure is the 40 Y/O plug which is plugged into the alternator, or is plugged into the APC if you have one fitted. Tha APC adds a connection point, which has new connectors on one side of each of the original fittings. It actually improves things, because it gets a clean surface into each connection. An intermittent connection will eventually fail the regulator if it's left to switch on and off or between twelve and 18 volts.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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